Mitsubishi Galant (2004+). Manual - part 1588

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-245

STEP 10. Recheck for diagnostic trouble code.

Check again if the DTC is set.
(1) Erase the DTC.
(2) Turn the ignition switch to the "ON" position.
(3) Check if the DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC B1476 or DTC B1477 set?

YES : Return to Step 1.
NO :  The procedure is complete.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-246

DTC B1486: Passenger’s seat belt warning Light Drive Circuit System Fault 2.

CAUTION

If DTC B1486 is set in the SRS-ECU, always diag-
nose the CAN main bus line.

.

CIRCUIT OPERATION

• Power for the passenger’s seat belt warning light 

is supplied from the ignition switch (IG1).

• The passenger’s seat belt warning light illumi-

nates when the ignition switch is turned to the 
"ON" position and goes out after approximately 
seven seconds if there is not a malfunction in the 
SRS system.

.

SRS-ECU

IGNITION
SWITCH (IG1)

JUNCTION
BLOCK

SEAT BELT
WARNING
LIGHT
(PASSEGER'S SIDE)

RELAY
BOX

JOINT
CONNECTOR (1)

TAILLIGHT
RELAY

FRONT ECU

JUNCTION
BLOCK

SEAT BELT
WARNING LIGHT
DRIVE CIRCUIT

Seat Belt Warning Light Drive Circuit

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-247

DTC SET CONDITIONS

• This DTC is set under one of the following cases 

while the SRS-ECU is monitoring the passen-
ger’s seat belt warning light drive circuit:

• When a short circuit occurs in the passen-

ger’s seat belt warning light drive circuit.

• When a malfunction is detected in the output 

transistor inside the SRS-ECU.

However, if the vehicle condition returns to normal, 
DTC B1486 will be automatically erased, and the 
passenger’s seat belt warning light will go out.

.

TROUBLESHOOTING HINTS

• Damaged wiring harnesses or connectors

• Malfunction of the SRS-ECU

.

DIAGNOSIS

Required Special Tool:

•  MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A (Vehicles with CAN 

Communication System)

STEP 1. Using scan tool MB991958, diagnose the CAN bus 
line.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958. Refer to "How to connect the 

scan tool 

P.52B-30

."

(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?

YES : Go to Step 2 .
NO :  Repair the CAN bus line (Refer to GROUP 54C, 

Diagnosis 

P.54C-14

).

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-248

STEP 2. Recheck for diagnostic trouble code.

Check again if the DTC is set.
(1) Erase the DTC.
(2) Turn the ignition switch to the "ON" position.
(3) Check if the DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?

YES : Check the passenger’s seat belt warning light drive 

circuit system (Refer to 

P.52B-249

).

NO :  There is an intermittent malfunction such as poor 

engaged connector(s) or open circuit (Refer to 
GROUP 00, How to Cope with Intermittent 
Malfunction 

P.00-6

).

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827